PROFESSOR AT KONIGSBERG 145 



known as the Vinea Domini. He then proceeded by Bingen 

 to Kreuznach, in order to make acquaintance with Thomson 

 before his projected journey to England. He writes to his 

 wife on August 6, 1855, that Thomson had made a deep 

 impression on him : 



' I expected to find the man, who is one of the first mathe- 

 matical physicists of Europe, somewhat older than myself, 

 and was not a little astonished when a very juvenile and 

 exceedingly fair youth, who looked quite girlish, came forward. 

 He had taken a room for me close by, and made me fetch 

 my things from the hotel, and put up there. He is at Kreuz- 

 nach for his wife's health. She appeared for a short time 

 in the evening, and is a charming and intellectual lady, but 

 in very bad health. He far exceeds all the great men of science 

 with whom I have made personal acquaintance, in intelligence 

 and lucidity and mobility of thought, so that I felt quite wooden 

 beside him sometimes. As we did not get through nearly all 

 we wanted to say yesterday, I hope you will let me stay over 

 to-day in Kreuznach/ 



The closest friendship and mutual esteem connected these 

 two great men for nearly forty years, until death separated 

 them. 



The last report from Konigsberg, on 'Work bearing on 

 the Theory of Heat in the year 1852,' had dealt with the 

 famous publications of William Thomson, and these were now 

 discussed by word of mouth at Kreuznach by the two great 

 legislators in the field of science. Thomson, after establishing 

 the already known law that the heat produced by animals, 

 together with the work done by them, is equivalent to the 

 chemical energies of their food and of the inspired oxygen, 

 had arranged the different sources from which mechanical 

 effect can be derived according to their origin, and came to 

 the conclusion that the heat radiating from the sun, including 

 its own light, is the principal source of all terrestrial processes, 

 and that the motions of the earth, moon, sun, with their mutual 

 attractions, are a potent source of kinetic energy, while an 

 exceedingly small portion only is of purely terrestrial origin. 

 The conclusion deduced by Thomson from Carnot's Law, to 

 the effect that the heat of the coolest body in the universe 

 will always persist as a work-equivalent, but cannot be 



